‘Psoriasis’ was one of the first skin diseases to be described. It was even referenced in the Old Testament, where the term ‘lepra’ was used to identify it; however, lepra was utilized for a wide variety of skin diseases, including a potpourri of conditions from leprosy to elephantiasis to vitiligo. Psoriasis has a wide spectrum of clinical expressions, and as a result has long been confused or lumped with numerous other skin diseases, including tuberculosis and syphilis. Psoriasis has been a confusing disease to identify because of the many patterns it displays and because a variety of different patterns may exist in the same patient. In essence, each psoriasis patient presents as a unique case of the disease. Today, some of the patterns and expressions of psoriasis are identified as plaque, pustular, guttate, inverse, erythrodermic, nail and arthritic. Psoriasis is a non-contagious chronic condition that most commonly appears as an inflamed edematous cutaneous lesion with built up silvery white scales, which form as a plaque. It is believed to be caused by unusually rapid growth of skin cells due to a derangement in the immune system. Drugs that affect the growth of cells, such as the anti-metabolites traditionally used in cancer treatment, have been used to treat psoriasis.